Metal display panel having one or more translucent regions

ABSTRACT

A metal structure ( 1 ) has a display region being a second region and being integrate with another region being a first region which is a display region. The metal structure may constitute a monolithic structure of an information display unit, for example, a front panel of an electronic device. The display region is formed by providing a cluster of small non-through-going cavities ( 5 ) in the metal structure, leaving a very small thickness of material, the thickness being translucent ( 6 ). In addition to being a display unit when arranging a light source behind the translucent region ( 6 ), touch sensitive or non-touch sensitive input devices, optionally connected to acoustical input and registration devices, may also be provided. These input devices may advantageously be arranged in, or adjacent, the cavities in the metal structure, whereby when the front of the metal structure is viewed an indication of display or input options is visible.

This application claims the benefit of PCT Application No.PCT/DK03/00126 filed Feb. 27, 2003 and PCT/DK2004/000113 filed 20 Feb.2004, which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to a metal structure with one or more translucentregions. The translucent regions may form symbols and thus the metalstructure may serve as an information display or input device.Accordingly, the invention also relates to an information display unitand/or input device and/or a combined information display unit and inputdevice incorporating such a metal structure.

BACKGROUND OF THE INVENTION

Display units for providing visual information by applying light from arear side of a transparent panel with pre-formed symbols are well-known.However, often such displays suffer from a number of disadvantages. Itis normally a prerequisite desire of the transparent panels that theinformation symbols are completely invisible in a deactivated state ofthe display, i.e. when the light source at the rear side of the displayis switched off. Therefore, transparent panels with a semi-transparentrear side or panels made of a semi-transparent material themselves areused as a front of the display so as to give a dark appearance in adeactivated state of the display. Coloured or toned glass or acrylicmaterials may be used in front of the display to provide this effect.

However, the display region will still be visible to a viewer also inthe deactivated state since most often the display will be made of afront material different from the front material of the device to whichthe display is attached, because often a front panel of a device is ametal panel, thus making it impossible to fully integrate the displayunit in the front of the device. The reason for the display panel notbeing fully integrated with the device front panel is that a transitionon the surface between the metal panel of the device and the non-metalpanel of the display will always be clearly visible and it will beperceptible if one touches the front surface. If a display panel isattached to a device having a metal front panel the difference inmaterials will also imply a non-perfect mechanical fit of the displayonto or into the front panel of the device. This non-perfect mechanicalfit will lead to further disadvantages than non-perfect visual fit asmentioned above. A border edge around the display panel will beinevitable. In addition, attaching a display panel to a front panel of adevice will normally involve a penetration of the front panel, such asfor electrical wires, thus introducing a path for dust, liquid and gasesthat may penetrate into the interior of the device thus disturbing thefunction of the device.

Attempts of producing a display front with an appearance similar tosolid metal is known, see for example the earlier application of theapplicant WO 03/019505. In this application the formation of a displayis described, where translucent regions are created in order to be ableto shine light through the metal structure. It thereby becomes possibleto display information on the surface of a metal structure where to theuser no obvious indications are present that the metal structure servesas a display unit. The document, however, does not describe that thestructure may also be used as an input unit, whereby it leaves theserious drawback that for applications, where it is desirable both todisplay information, but also to receive input, the skilled person willhave to provide separate input means, for example in the shape oftraditional bottoms, dials, etc. This in turn necessitates that firstlyan area of the device where such a structure is built into needs to belarger in order to also accommodate the input means, but also the “pure”design where the surprising effect of having an entire clean metalsurface is lost.

In other applications, display fronts which appear to be solid metalhave been attempted such as a metal layer being vapour deposited onto atransparent surface thus providing a translucent surface. However, as anexample, a glass material must still be used for supporting the metallayer and thereby the visual appearance of an integrated display regionand front panel is destroyed. Other attempts to produce displays withmetal-like fronts have several layers. Such displays typically have afront sheet of a transparent material positioned in front of a metalsheet thus to a certain degree providing a visual impression of a metalsurface.

U.S. Pat. No. 5,987,793 describes a display unit with pre-formed symbolsvisible from a front side when a light source is applied at a rear side.The display unit has several layers. A transparent sheet forms a frontof the display. A 0.01-0.05 μm thick layer of metal, for examplealuminium, is applied to the rear side of the transparent sheet. Symbolsare formed in a “character cut-out layer” behind the metal layer. Thesymbols are visible from the front side, when the light source at therear side is switched on. Without light being switched on at the rearside, only the metal layer is visible from the front side thus giving avisual impression of a metal display. In order to provide a “high-gradefeeling” the front side of the transparent panel is coated with a layerof urethane resin.

U.S. Pat. No. 4,417,411 describes a display with a front panel of atransparent material coated with a metal coating with a thickness of200-300 Å. The metal coating is intended to provide a visual impressionof a “metallic wall”, when light at the rear side is switched off.

FR 2 702 296 A3 describes a display with a front sheet being translucentbut not transparent. A thickness of 0.1-0.5 mm is considered appropriatefor the front sheet, depending on which material is used. The frontsheet is positioned in front of a second sheet, for example a metalsheet, the second sheet not being transparent or translucent.Transparent symbols are canted into the second sheet so as to allowsymbols to be visible from the front when a light source is applied fromthe rear side.

JP 2002040952 (English abstract) describes a display with a metal filmhaving a large number of small cavities with a pore diameter of 5-70 μmin a specified pitch by about −20-50% area rate of view area is formedon an upper face side of a transparent substrate. A colour image-forminglayer is formed on the upper face side of the metal film, and atransparent protective film layer is formed on the upper face of thecolour image-forming layer. An effect being obtained with the describeddisplay is a “noble metal appearance”.

JP 2002023670 describes a display with a metallic film in which smallcavities having about 40-70 μm diameter are dispersively arranged atprescribed intervals about 20-50% area rate of the surface area isarranged on the lower face of a transparent display substrate.

It is an object of the present invention to provide a metal structurethat can serve as a front panel and at the same time allow informationto be displayed on a display region of the panel, when a light source isapplied on a rear side of the structure. However, the object includesthat when the light source is switched off, the display region shouldnot in any way be distinguishable from the remaining part of the panel.

SUMMARY OF THE INVENTION

The above-mentioned objects are obtained according to a first aspect ofthe present invention, by providing metal structure with one or moretranslucent regions, where the unit has a front side suitable forinteraction with a user, where said front side is visually homogeneousand a back side opposite the front side, where said one or moretranslucent regions is/are formed by providing non-through goingcavities in the back of the metal structure, leaving a very smallthickness of material, said thickness being translucent, and thatfurther means for arranging a light source in the cavity or in thevicinity of the cavity is provided, and that further means for detectinginput is provided in the cavity or in the vicinity of the cavity.

By ‘translucent’ is understood: permitting light to pass through, butdiffusing it so that persons, objects etc. on the opposite side are notclearly visible. This is in contrast to ‘transparent’ which means asubstance transmitting rays of light so that objects situated behind canbe distinctly seen. An example of a translucent object is frosted windowglass.

The thickness mentioned is dependent on the material in question ofwhich the metal structure is made and is dependent on the luminousintensity of the light source and the luminous intensity of the lightbeing transmitted. Accordingly, the thickness of the bottom of thecavity may be as small as 10 nm. Therefore, by a material thickness isunderstood a spatially averaged thickness of material in a region inquestion, when viewing the region in a cross-sectional view. For verysmall thicknesses of material microscopic protrusions of one or bothsurfaces, between which the thickness is to be measured, may cause theactual thickness to vary considerably throughout a region. For suchsmall thicknesses the type of spatial average adopted in the presentinvention is spatial average of the region in question with respect toits ability to transmit light with a wavelength in the visible range,e.g. 400-750 nm. Therefore, a region of aluminium having a thickness ofperhaps 30 nm according to the present invention has a lighttransmission corresponding to a sheet of aluminium with a homogeneousthickness of 30 nm. The actual thickness of material of the region mayas example vary between 2 nm and 200 nm with a dimensional averagethickness of 30 nm. It should be noted that with the thicknessdefinition according to the present invention the determined thicknessmay depend on the wavelength of light applied. Consequently, comparingtwo thicknesses is only meaningful if determined for the same type oflight, for example monochromatic light with a certain wavelength.

The metal structure according to the first aspect may be monolithic.Preferably the cavities have a light transmission rate of at least 0.1%.Clusters of cavities may be formed. Each of the cavities of the clustersmay be substantially cylindrical, and they may have a diameter withinthe range 1-100 μm. The clusters may form the shape of a symbol and/ormay form a matrix of dots.

The metal structure may be selected from the group consisting of:aluminium, magnesium, zinc, titanium, stainless steel alloys, copper,and brass.

The metal structure may further comprise a translucent or transparentprotective layer at its front side. The protective layer may be selectedfrom the group consisting of: lacquer, coating, varnish, vitreousenamel, ceramics, oxide, and oxide obtained by anodization.

The metal structure may further comprise a translucent or transparentsupporting layer positioned on the rear side of the metal structure. Thesupporting layer may be selected from the group consisting of: glass,ceramics, polymers, and silicone rubber.

An illuminative display unit comprising a metal structure and a lightsource, wherein the front side of the metal structure forms a surfacefor visual display of an image when transilluminated from the rear sideby light provided by the light source may also be contemplated withinthe scope of the present invention. The image may comprise a predefinedsymbol formed by a shape of the second region of the metal structure.The light source may be positioned on the rear side of the metalstructure. The light source may be positioned exterior to the displayunit, and the light source may comprise means for guiding light to therear side of the metal structure into the cavities or in the vicinity ofthe cavities. The light source may be selected from the group consistingof: glow lights, LEDs, CRTs, and lasers.

The light source may comprise a display screen adapted to form the imageto be displayed. The display screen may be selected from the groupconsisting of: Thin Film Transistor (TFT), Cathode Ray Tube (CRT),Liquid Crystal Display (LCD), Light Emitting Diode (LED), Organic LightEmissive Diode (OLED), Light Emitting Polymer (LEP), Field EmittingDisplay (FED) and Plasma The display screen may be adapted for formingdynamic images.

In a further advantageous embodiment the means for detecting user-giveninput commands are touch sensitive, such as for example capacitanceelements, piezo-electrical switches, strain gauges, micro-switches,pressure sensitive foils or other suitable devices for detecting touchinput.

One of the main advantages with the present invention is the fact thatthe surface of the device where a display and input unit according tothe invention is built into does not appear to have any informationmeans or input devices such as buttons and the like. As the device isactivated and the display and input unit is illuminated, a user will beable to see information on the surface of the unit. Furthermore, theunit may be provided with zones which a user may touch in order to givean input such as for example the selection of a radio station, volumecontrol, a number or the like. The touch sensitive means may for examplebe a capacitance element. Capacitate elements work in the way that aelectrical potential is present between two conductive areas. One ofthese areas might be the surface of the unit and the other conductivearea may be arranged inside the cavity. As a user touches an area wherethe capacitance element is arranged, the electrical potential betweenthe two surfaces will change and thereby make it possible to detect thatan input signal has been activated. Another touch sensitive input meansmay be a so-called piezo-electrical switch where a light pressure on thepiezo-electrical switch also generates a current and thereby an inputsignal. The translucent areas of the cavities are so thin that theymight deflect when touched unless a reinforcing means has been arrangedinside the cavity. This deflection of the metal layer in the bottom ofthe cavity may provide input for strain gauges arranged across thebottom of the cavity such that, as the strain gauges are activated andthereby also the electrical current through the strain gauges ischanged, an input signal is generated. The same deflection of the metalmay be used in order to activate micro switches arranged in thecavities.

Also, a touch-sensitive foil which is commercially available may bearranged in the cavities, such that when a user touches the unbrokensurface in designated areas, the pressure will be transmitted throughthe metal to the touch-sensitive foil. This embodiment is particularlyinteresting in cases where the touch-sensitive foil is transparent suchthat it is possible to transmit the light from the light source throughthe foil, through the cavities and through the translucent sections ofthe unit. A layer of piezo-electrical crystals can be evaporated ontothe cavities to act as a touch sensitive foil. Furthermore, it should bementioned that other suitable devices, for example originating from nanotechnology may be implemented in order to detect the touch input fordevices of the type described above.

In a still further advantageous embodiment the means for detecting inputare not touch-sensitive, such as for example optical means. Thisembodiment is especially advantageous in use where the surfaces for thedisplay and input unit is part of the surface for an electronic devicesuch as for example a radio, hi-fi, television, oven, cooker,refrigerator and the like, where it is desirable to provide the userwith an aesthetically pleasing surface, for example in the form of abrushed aluminium or brushed stainless steel surface. In order to avoidthe stains and marks from touching the surface which necessitatecleaning in order to achieve the pleasing surface characteristics andappearance again, the optical means does not require the user toactually touch the unit in order to provide the desired input.

The inventive concept of the present invention as set out above isparticularly interesting in an electronic device comprising a displayunit according to the invention. The electronic device may be selectedfrom the group consisting of: audio equipment, visual equipment,communication equipment, and auxiliary equipment.

The audio equipment may be selected from the group consisting of: hi-fiequipment, active loudspeakers, Audio-Visual multimedia equipment,portable audio equipment, Car-fi equipment, and In-Car entertainmentequipment.

The visual equipment may be selected from the group consisting of: TVsets, computer screens, laptop computer screens, palm computer screens,Audio-Visual multimedia equipment, digital still cameras, motion picturecameras, transportation vehicle instruments, car instrumentation, traininstrumentation, aircraft instrumentation, marine vesselinstrumentation, and spacecraft instrumentation.

The communication equipment may be selected from the group consistingof: mobile communication equipment, mobile phones, telephones, and radioequipment.

The auxiliary equipment is selected from the group consisting of:electronic watches, domestic appliances, kitchen equipment, foodprocessing machines, medical devices, health care equipment, electronicgames, amusement equipment, exercising machines, electronic controlledfurniture, home entertainment equipment, measuring equipment, handheldmeasuring equipment, and remote controls.

The applications above shall not be considered to constitute anexhaustive list of applications. The skilled person and especially adesigner will be able to recognise further applications where theinventive features of the invention are advantageous.

In a further application, an input and display unit according to theinvention is used as an outer part of a cabinet of an electronic device.The metal structure may form at least a front part of the cabinet.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in detail withreference to the accompanying drawing, where

FIG. 1 are sketches of the principle of a simple embodiment of theinvention,

FIG. 2 are sketches of the principle of a preferred embodiment of theinvention,

FIG. 3 are sketches of the principle of a preferred embodiment of theinvention,

FIG. 4 are cross-sectional views showing a front panel of a displayregion with the appearance of a symbol together with a magnified view ofa detail of the symbol,

FIG. 5 is a sectional view of a display unit having a protective surfacelayer, a supporting structure and a light source,

FIG. 6 illustrates a structure where it is both a display and an inputunit.

While the invention is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. Itshould be understood, however, that the invention is not intended to belimited to the particular forms disclosed. Rather, the invention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The technical effect of the invention is that the metal structure can beused for display of information when viewed from a front side of themetal structure. A display region has shapes so as to form symbolsintended for providing a viewer with information when a light source isswitched on at a rear side of the metal structure. With the light sourceswitched off, the front side of the metal structure has the appearanceof a solid metallic surface—both with respect to visual and touchableappearance and with respect to structural appearance. In the mode wherethe light is switched off, the appearance is such that no indication isgiven to a potential user that the input display unit is different fromany other metal structure made from the same material. As example, themetal structure may be a plate, a sheet or a foil of aluminium,magnesium, titanium, zinc, brass, stainless steel alloys, copper or thelike. Chemically plated metallic surfaces on a metal basement such aschrome on nickel may also be used. In addition, physical vapourdeposition (PVD) evaporated metallic coatings such as TiCN, TiAIN, CrNetc. may be used. Metals having a natural hard and stable oxide layerbeing transparent or translucent are preferred.

According to the invention it is possible to integrate a display in afront of an apparatus, the display being invisible to a viewer in adeactivated state, i.e. when the light source is switched off. The frontside of the metal structure may have a polished or brushed surface so asto serve as a front of an apparatus such as TV sets, hi-fi equipment ora large variety of other electronic equipment where, for example, a“clean” homogeneous appearance is desired in a deactivated state,whereas information regarding the function of the equipment is requiredin an active state, i.e. when the light source is switched on.

FIG. 1 shows a simple embodiment according to the invention. A metalstructure 1 being a plate, a sheet or a foil of metal 2 has a front sideor surface 3 and a rear side 4. The metal structure 1 has cavities 5formed in order to produce regions 6, where the metal is thin enough tobe translucent so as to allow light to penetrate the metal. The cavitieshave a very small cross-section, such as ranging from 40 μm to 100 μmfor aluminium.

A light transmission rate (degree of transmitted light energy) of theorder of 0.1% may be appropriate for some applications. However, a lighttransmission rate of 1% is preferred in most applications, and a lighttransmission rate of 10% is even more preferred. In case of aluminium atransmission rate of 0.1% of light with a wavelength of 550 nm (greenlight) can be expected to be obtained with a material thickness of 35-40nm. A transmission rate of 1% can be obtained at a thickness of 20-25nm, and a transmission rate of 5% can be obtained at a thickness of12-14 nm.

If the light penetrating the metal structure in the regions 6 is visuallight, an intensity of light-perceived by the human eye depends to alarge degree on the total amount of light being transmitted though theregions, since the cavities are so small that it is not possible for thehuman eye to see light transmitted through a single cavity. Only closelyspaced clusters of cavities can be seen as a symbol displayed by light.Therefore, the visibility of the displayed symbol depends not only onthe light transmission rate of each translucent region, but also on thetotal area of this display region, said total area being the sum of theareas of all cavities within the display region. With a given diameterof the translucent regions an important factor is therefore how closethe cavities can be spaced while still not causing the metal structureto be so weak because of to closely spaced cavities that visual defectssuch as cracks will occur on the surface 3.

The cavities must be so deep that only a translucent thickness of metalis left, but still the remaining material thickness must be sufficientlylarge so as to maintain a structural integrity of the material and anintegrate visual appearance of the front side of the metal structure. Iftoo much material is removed, when forming the cavities, it may resultin visible cracks on the front surface thus destroying the visualappearance and the structural integrity. Possibly, a layer of a commonlyused metal lacquer or oxide layer on light alloys as anodizing may beapplied to the front surface prior to forming the translucent secondregions. This layer has a supporting effect on the thin translucentmetal layer of the second regions so as to minimise the risk of thecavities causing any cracks or any other visual or structural defects ofthe front surface.

The cavities formed in the metal material may have any cross-sectionalshape. The actual shape may depend on the process for creating thecavity. When for example a laser is used, it may be advantageous tocreate round cavities (non-through-going cavities), but in otherinstances when for example an ablation or etching process is used, thecavities will have a random cross-section. When reference therefore ismade to the diameter of the cavity, the intended meaning is the meanaverage diameter.

In FIG. 2 is illustrated a further preferred embodiment wherein thecavities 5 are provided at the bottom of a second larger cavity 10.Although the embodiment explained above with reference to FIG. 1illustrates the inventive principle, it may for practical and economicreasons be advantageous to first create a second larger cavity andthereafter create the small cavities 5.

This embodiment allows for larger light sources to be utilised, closerto the surface 3 of the metal structure 1. Furthermore, the secondcavity 10 may be shaped corresponding to the desired display or inputsign, desirable on the surface, such that by providing one light sourcein the second cavity 10 and optionally light diffusing means or lensmeans the one light source may be utilised for illuminating the desiredshape through the cavities 5 and the translucent region 6 on the surfaceof the structure.

Furthermore the cavities being of such small cross-sections and withvery small centre to centre distances, see above requires a very highdegree of precision. By creating the second larger cavity 10 the depthof the cavities 5 may be more shallow, whereby it becomes cheaper andeasier to provide the necessary precision, in that the actual removal ortransformation of material from the cavities is minimised.

FIG. 4 shows a front view of a display unit 100 formed by a metal sheetcapable of displaying the pre-selected symbol ‘>’ on its front surface110, when a light source positioned at a rear side of the display 100 isswitched on. In FIG. 4 the light source is turned on and the shownraster of light dots 120 forming the symbol indicate a visual impressionas observed by human eyes. The magnified view shown in the bottom partof FIG. 4 indicates that each visual light dot 120 consists of a clusterof even smaller single translucent dots 130 closely spaced so as to forma visual impression of a single dot 120. In case of an aluminium sheet asuitable thickness of material for providing a translucent region 130 isin the order of 10-30 nm. In aluminium, the cavities may have a diameterin the order of 40 μm and they may be positioned with a centre-to-centredistance of 100 μm. A light transmission rate of 1% or more is possiblestill without obstructing structural integrity of the surface 110.

In order to enable the very close positioning of cavities with such asmall diameter, learning a very small thickness of metal, the cavitiesshould preferably not be too deep. Closely spaced deep cavities requirea very high precision with respect to the orientation of the cavities. Acentre line of the cavities should be perfectly parallel in order not tomerge, thus causing the metal structure to be weaker than if the regionbetween the cavities is kept intact. Therefore, in case of metal plateswith a thickness in the order of mm, before preparing the cluster ofcavities in a shape forming symbols, it is preferred initially to removematerial so as to form a an intermediate region (second region)constituting a cavity on the rear side of the metal plate in a regioncovering the desired display region. In addition, production time issubstantially decreased if an intermediate thickness of material isestablished prior to the process of forming the translucent regionshaving the smallest thickness. However, this intermediate thicknessshould still be sufficient for not causing poor structural stability ofthe remaining metal structure, such poor structural stability of anysuch intermediate region resulting in defects on the front surface ofthe metal structure. The thickness of the second region thus has athickness being smaller than the first thickness of the entirestructure, but larger than the thickness of the material in the bottomof the cavities.

The process chosen for forming a cavity having an intermediate thicknessmay be chosen according to the type of metal selected. For instance insome materials it may be expedient to use milling, or turning, orgrinding, whereas others would work well with the much faster operationof calibrated partial punching, in which the material flows. The formingof the cavity may occur before or after any optional surface texturing(which is to be regarded as separate from surface protection), which maytake place by brushing, shot peening, or grinding. The creation of thecavity may be a multi-step process comprising electro-erosion, etching,and a Nd-Yag ablation process

FIG. 4 shows a sectional view of a display unit 100 with a surface 110adapted to display an image formed by a raster of light dots in areas130, where cavities 135 are formed in the metal structure 105. Note thatFIG. 4 shows a principal sketch, the proportions of the features shownare not necessarily correct, i.e. the cavities 135 are shown withexaggerated size.

In FIG. 5 the metal structure 105 has a protective layer 115 of anodizedoxide or metal lacquer thus providing a surface being resistant totouching of the front side surface 110, resistant to various substancessuch as deposits from human fingers touching the front side surface 110,and resistant to various objects that accidentally may hit the surface110. The choice of lacquer, varnish, enamel is well-known for theskilled person. The enamel may be vitreous for alloys and pure metalshaving a melting point above that of the enamel in question.

In order to further improve the strength of the metal structure, thedisplay 100 is provided with a supporting structure 140 in the areabehind the cavities 135 as illustrated in FIG. 5. The supportingstructure 140 supports the outer layers 105, 115. The supportingstructure is preferably transparent so as to allow a large portion oflight provided by the light source 150 to penetrate to the cavities 135and further to the surface 130. The supporting structure 140 may be adimensionally stable compound. It may be a polymeric material applied,while in a viscous state, from the rear side of the metal structure. InFIG. 5, the supporting structure 140 is shown not to fill the cavities135, however it may be preferred to apply a supporting structure 140 ofa material that has a viscosity, which when applied will allow thematerial to fill the cavities 135 as well, thus providing extra strengthto the metal structure 105. It is important that the compound neitherexhibits shrinkage nor expansion during curing since this would entailchanges in appearance of the front surface 110 of the display and,furthermore, that the compound has similar temperature expansioncoefficients as the metal material.

The light source 150 sketched in FIG. 5 may be an array of LEDs, such asred, yellow, green, blue or white LEDs or an array of combination ofcolours. The LEDs may also be adapted to emit light with two differentcolours such as red or green, thus providing a possibility of a threestate display region with the three possible states being: no symbol,red symbol, green symbol. Preferably, the LEDs are types of LEDsproviding a bright light so as to allow a light symbol to be visible bythe human eye in normal daylight also at a distance of more than 1 m. InFIG. 5 the light source 150 is shown to be positioned adjacent to thesupporting structure 140. This may be preferred so the light source 150can be positioned as close as possible to the surface 110 so as togenerate the brightest light possible with a given light source 150. Itmay also be preferred to position the light source 150 remote to themetal structure 105 and use light guiding, such as optical fibres or anoptical lens.

A practical example is as follows: a thin sheet of 10 mm diameter wasprepared in a piece of aluminium by turning on a lathe to a thickness of100 μm. This was subsequently anodized to a thickness of 15 μm of theoxide layer on either side. This semi-product was exposed to theablative laser treatment according to one aspect of the inventionperformed at Laser-Laboratorium Göttingen e.V., P.O. Box 2619, D-37016Göttingen, Germany. A number of square “dots” 1 mm×1 mm were formed inthe prepared thin sheet, until a translucency of 0.1% was obtained foreach “dot”. Each dot consists of a grid of 10×10 essentially cylindrical(but in practice slightly conical) micro cavities each 40 μm in diameterand a centre-to-centre distance of 100 μm. Closer inspection of a cavitydisplays a slightly edgy cross section. A UV-Excimer femto second laserwas used, and a CCD camera was used on the side of the sheet not beingtreated in order to determine when the appropriate translucency for anyone micro cavity had been obtained, whereupon the laser beam was stoppedand moved to the next location in the grid. In some cases, the finaltransparency of individual micro cavity was considerably higher, becauseof a depletion of aluminium due to surface roughness. However visualinspection of the front of finished articles, even under a microscope(×100 magnification) and angled illumination from the side did notreveal the location of these spots of higher transparency, and they arehence considered to be insignificant in a practical product. A LED wasfitted in the cavity on one side of the thin sheet, and the otherside—the front—was observed both in daylight and in the dark. The dotpattern was clearly visible as emanating from the solid aluminiumsurface in a viewing angle of 120°, and in broad daylight a red lightwas clearly visible at a distance of maximum 3-4 m. A blue diode wasless visible, the maximum distance being only 1 m. When the LED wasturned off, there was no visible trace of the laser ablation treatmenton the front surface which appeared totally uniform, even when ahand-held magnifier was used.

A metal structure according to the present invention has a large numberof possible fields of applications on equipment, where it is possible toutilise the metal structure as a structural part of an enclosure, suchas a cabinet of an electronic device, and at the same time provide thepossibility of presenting information symbols on one or more surfaces ofthe enclosure. Especially, the metal structure can serve as a frontpanel, such as a control panel of an electronic device, having a displayregion being integrate with the remainder, or at least part of theremainder, of the front panel.

A simple application of a combined front panel and display may be a“hidden” stand-by indicator in for example a hi-fi loudspeaker withintegrated power amplifier. If not used for a certain period of time alight indicator on the front of the loudspeaker will indicate that theloudspeaker has turned to a stand-by mode. Such a stand-by indicator mayaccording to prior art be implemented as an LED mounted in a cavitythrough the front panel of the loudspeaker. With the present inventionit is possible to avoid a perforation of the front panel, and in anactive mode of the loudspeaker the stand-by indicator is invisible. Inmost embodiments of the invention the display region, when in anactivated state, is intended for being visual to the human eye. However,in other embodiments, the display region, or perhaps just part of thedisplay region, may be visible only to optical reading means monitoringand/or controlling functions of the device depending on whether thedisplay region, only being-visible to the optical reading means, isactivated or not.

If a front panel has a display function according to the presentinvention in combination with control means formed as invisible touchsensible zones it is possible to completely avoid any perforation of thefront panel. Positions of the touch sensible zones may be indicated bydisplay regions instead of by printed symbols on the surface of thepanel. Hereby, it is possible to form a smooth and integrated surfaceeliminating possible penetration of dust, dirt or liquids that maydisturb the function of the equipment behind the front panel. Thesurface also becomes easy to clean since cleaning or washing of thesurface is improved, because of no control means or display meansprojecting from the surface. An additional possibility is to completelyhide control facilities and functions of the device in a deactivatedstate, where the display function is switched off. In fact it ispossible to have a completely blank surface in a deactivated state ofthe equipment.

According to the present invention it is possible to provide a displayunit capable of showing dynamic images, such as motion pictures so as tobe able to serve as a screen for a TV set, a computer screen or a screenon a mobile phone. The display unit sketched in FIG. 5 may have cavitiesarranged so as to form pre-selected symbols such as the display unitshown in FIG. 4. However, according to the invention it is also possibleto form symbols by applying light to only selected parts of the secondregion. The display unit sketched in FIG. 5 may be adapted to showmoving pictures if cavities 135 are produced in a cluster forming araster, for example, a rectangular area corresponding to a screen size.In this way a matrix of cavities 135 will form a translucent area thusallowing any symbol to be formed by applying light to a symbol shapedpart of this translucent area. The light source 150 to do this may be aLCD, TFT or CRT colour or monochromatic display screen or any otherdisplay screen capable of providing a light intensity required toproduce an image with a sufficient light intensity on the surface 110.For certain applications with high demands for a display with a highlight intensity the light source 150 may be a LCD display positioned infront of a glow light based lamp. The light source 150 may also be a LEDdot-matrix display screen.

Within instrumentation for all types of vehicles a display unitaccording to the invention may be appreciated. A display forinstallation in a car may include speedometers, rotation speed meters,fuel tank meters, engine temperature meters, warning lights etc. A“night panel” function is easy to implement where for example onlyspeedometer is permanently illuminated at night, and wherein otherinstruments are illuminated only when providing relevant information tothe driver. In this way a large number of instrumentation lights areavoided thus a disturbing factor due to traffic security is eliminated.Also in daylight it is easy to avoid irrelevant information since theinstrumentation can be implemented so that only relevant instruments arevisible on the instrumentation panel.

For exterior use within vehicles, such as cars, a flashing indicator canbe integrated with the body of the car. Hereby no perforations of thebody plates are necessary, thus a potential corrosion factor iseliminated. In addition, a smoother surface without a protrudingflashing indicator lamp is beneficial with respect to both windresistance and with respect to security for pedestrians in case ofcollision.

When also having the built-in input facilities as discussed below, itbecomes possible to use numeric combination car locks, where the input“pad” is part of and integral with the exterior cladding of the car.

A display unit according to the invention may be appreciated for a largenumber of applications where an apparatus capable of displayinginformation is combined with a high degree of resistance against dirtand humidity. For example within medical equipment where a display unitaccording to the invention will be easy to disinfect since the front canbe made smooth without any protrusion. In addition, it is possible touse liquids for cleaning/disinfecting without damaging the apparatusinto which the display unit is integrated. The resistance to penetrationof liquids may also be appreciated within handheld measuring instrumentsadapted for measurements within humid and dirty places, such as voltmeters, sound level meters etc.

The present invention also enables creating of display units and therebyapparatuses with an aesthetic effect since the appearance of anapparatus is not necessarily dictated by technical considerations. Thisleaves a large degree of freedom to design with respect to aesthetics.It is possible to produce a very “clean” surface if desired, oralternatively the surface can be decorated or formed purely influencedby aesthetics not being limited by technical considerations.

Above the advantages of the invention relating to use as a pure displaydevice have been described. The inventive structure may, however, alsobe used as a combined display and input unit.

In FIG. 3 is illustrated an example where a number of cavities 5 areformed in a structure 1. The general construction of the metal structurecorresponds to the structure described with reference to FIG. 2.

In this embodiment, however, a touch-sensitive foil 50 has been arrangedimmediately adjacent the openings of the cavities 5. As the surface 3 ofthe structure 1 is depressed, the depression for example deriving from auser touching the surface 3 will be transmitted to the foil 50, and fromthe foil via an electrical connection 51 on to appropriate circuitry(not shown) for example arranged on a printed circuit board.

In order to indicate to a user the available option of inputtinginstructions in the specific region 6 comprising the cavities 5, asuitable display as discussed above should be provided and illuminatedsuch that the translucent properties of the structure are utilised inorder to indicate the desired type of information and input options.This may be facilitated by arranging a light source 52 in the secondcavity 10. In this connection it should be mentioned that transparent orhighly translucent touch sensitive foils 5-o are preferred, as theemitted light from the light source 52 must be able to pass through thefoil and the translucent regions 6 of the structure 1.

Optionally, a lens or light diffuser 56 may be arranged between thelight source and the foil in order to create and provide an eventranslucency in the structure and thereby an evenly lighted symbol onthe surface 3 of the structure 1.

In order to further improve the light intensity the light source may beprovided with light reflector means 55. In practice the light sourceincluding reflector means is arranged on a printed circuit board (PCB)and lens as well as touch sensitive foil means is also pre-arranged inrelation to the light source in the desired pattern. Before arrangingthe light in the second cavity 10, the cavities are filled with apreferably transparent filler material, for example an epoxy basedresin. In this manner the display means and the input sensor (the touchsensitive foil) are integrated into the reinforcing structure of thesecond cavity 10.

In use the embodiment as illustrated with reference to FIG. 2, will bothdisplay information or input options and register any input made by auser when touching the region 6.

In FIG. 6 is also illustrated an embodiment of the invention where thestructure serves both as display and input unit. In this embodiment theinput is registered by means of capacitance. The surface 3 of thestructure 1 is coated with an isolating layer 53. On top of theisolating layer 53 is arranged a transparent electrically sensitivelayer 54 and optionally a transparent protective layer on top.

The light source may be arranged as described above with reference toFIG. 3.

As a user touches the region 6 where the layers 53 and 54 are arrangedthis will cause a change in capacity in the electrically sensitive layer54. As was the case in the embodiment described with respect to FIG. 3,this electrical input is detected and transferred to appropriateelectronic circuitry (not shown) via electrical connection means 51.

Common for both embodiments illustrated in FIGS. 3 and 6 is that thecavities 5 may be filled with a transparent filler 57. The fillermaterial may be epoxy based, and the material is for example evaporatedinto the cavities 5. It is important to choose a material with materialproperties relating to thermal expansion which is substantiallycorresponding to the corresponding properties of the metal structure 1.

Alternative to the capacitive sense option described in FIG. 6, theinput detection may be by means of piezo-electrical or strain-gauge unitprinciples, as shown in FIG. 3.

An example of a piezo-electrical unit is products such as AlgraDynapic/Dynasim from Algra AG. These piezo-electrical units arerelatively small size, and very small depressions of the surface 3generates voltage which can be detected as an input signal.

Examples of strain gauge units are Force Sensor Resistor from InterlinkElectronics Inc. Very small depressions of the surface 3 can be detectedas changes in the impedance value of the sensor, which then is detectedas an input signal.

In a further embodiment (not illustrated) the display and input unit isdesigned as a non-touch unit. This is achieved, for example, byarranging the end of an optical fibre in the second cavity 10. Theoptical fibre is itself the source and sensor as a light detectionelectronic unit. The input detection is based on breaking the modulatedlight wave issued from the unit, i.e. the optical fibre, and sensing thereflection. The light may preferably be of infrared wavelength modulatedonto a carrier frequency and optionally data coded in order to allowindividual address capabilities per fibre or for a group of fibres.

Common for the touch type display and input units contemplated withinthis invention is that a tactile feed back may be built into the inputregion, such that a user gets feedback when inputting.

Common for both the touch type and the non-touch type units contemplatedwithin this invention is that an acoustical signal may be issued whenthe input has been registered. Furthermore a delay may be built into theissuing of the signal, such that it requires that the user for a certainperiod of time activates the input means. In this manner accidentalinput may be avoided or at least minimised.

Input may also be varied, such that for example a first briefregistering of input, activates a light source and/or an acoustic signalis generated, whereby for example the display is illuminated in thetranslucent regions, for example as the finger of a user passes thedisplay and input device, a number of acoustical signals may begenerated in response to activation of the touch or non-touch sensormeans. These signals indicate the regions where a central display orinput region is located. The user may thereafter seek and activate thedesired information and/or input. In this situation the inputregistering may be delayed as described above.

Also different types of sensing options may be chosen in one structure,such as touch and non-touch, as well as different means for detectingthe input.

1. An information display and input unit comprising a metal structure(1) with one or more translucent display regions (6) integrated with anon display region, wherein the metal structure has a front side (3)suitable for interaction with a user, wherein said front side (3) isvisually homogeneous, and a back side (4) opposite the front side (3),wherein said one or more translucent display regions (6) is/are formedby providing non-through going cavities (5) extending from the back sidepartially through the metal structure (1), leaving a very smallthickness of material, said small thickness of material beingtranslucent, and that further comprising means for arranging a lightsource in the cavities (5) or in the vicinity of the cavities (5), andmeans (50,54) for detecting input is provided in the cavities (5) or inthe vicinity of the cavities (5).
 2. The unit according to claim 1,wherein the means (50,54) for detecting input are touch sensitive. 3.The unit according to claim 1, wherein the means (50,54) for detectinginput are non-touch sensitive.
 4. The unit according to claim 1, whereinthe means (50,54) for detecting input are connected to acoustical meansand/or illumination in the one or more translucent display regions, andregistration of input is linked to acoustical signals and/orilluminations in the translucent display regions.
 5. The unit accordingto claim 4, wherein a first acoustical signal and/or illumination in theone or more translucent display regions may indicate that a user is inan input region and a second acoustical signal and/or illumination inthe translucent region may indicate that an input has been registered.6. The unit according to claim 1, wherein a light source (52) isprovided, and said light source (52) may comprise reflecting means (55)arranged for directing the light emission towards the one or moretranslucent display regions (6).
 7. The unit according to claim 3,wherein the light source (52) is one or more optical fibres mounted instructures in the vicinity of one or more cavities (5), and furtherwherein the fibres are connected to a light detection electroniccircuit, such that alterations in the emitted light is recognised as aninput.
 8. The unit according to claim 1, wherein one or more cavities(5) may be arranged in a secondary cavity (10), wherein across-sectional area of the secondary cavity (10) is substantiallylarger than a cross-sectional area of the one or more cavities (5). 9.The unit according to claim 8, further comprising an information displayand input unit comprising the metal structure (1) with the one or moretranslucent display regions (6), wherein the unit has a front side (3)suitable for interaction with a user, where said front side (3) isvisually homogeneous and a back side (4) opposite the front side (3),where said one or more translucent display regions (6) is/are formed byproviding non-through going cavities (5) in the back of the metalstructure (1), leaving a very small thickness of material, said smallthickness being translucent, further means for arranging a light sourcein the cavities (5) or in the vicinity of the cavities (5) is provided,and means (50,54) for detecting input is provided in the cavities (5) orin the vicinity of the cavities (5) arranged in the secondary cavity(10).
 10. The unit of claim 8, wherein the cavities inside the secondarycavity are filled with a transparent filler (57).
 11. The unit of claim10, wherein the transparent filler is an epoxy based filler.
 12. Theunit of claim 6, wherein a light diffuser and/or lens (56) is arrangedbetween the light source (52) and the one or more translucent displayregions (6).
 13. An information display and input unit comprising ametal structure with one or more translucent regions, wherein the metalstructure has a front side and a back side opposite the front side,wherein the front side is suitable for interaction with a user, whereinsaid front side is visually homogeneous, wherein said one or moretranslucent regions are created by providing cavities from the back sideof the metal structure terminating short of the front side, such that amaterial thickness in the ends of the cavities is translucent throughthe metal structure that remains at the ends of the cavities, lightsources in the cavities or in the vicinity of the cavities, and inputdetectors provided in the cavities or in the vicinity of the cavitiesfor detecting inputs from, on or near the ends of the cavities.
 14. Theunit of claim 13, wherein the metal structure has a first region whichis not a display region, wherein the cavities are formed in a secondregion of the metal structure which is a display region, and wherein thefirst and second regions are integrated.
 15. The unit of claim 2,wherein the means (50,54) for detecting input that are touch sensitiveare devices selected from the group consisting of capacitance elements,piezo-electrical switches, strain gauges, micro-switches, pressuresensitive foils, and combinations thereof.
 16. The unit of claim 3,wherein the means (50,54) for detecting input that are non-touchsensitive are optical means.
 17. The unit of claim 7, wherein thealterations in the emitted light are reflections.
 18. The unit of claim7, wherein the alterations in the emitted light are variations in wavepatterns.
 19. The unit of claim 7, wherein the alterations in theemitted light are modulations in wave patterns.